Improvement in saw-mill set-works



J. A. ROBIB. SAWMILL SET-WURKS.

No. 195,650. "Patented Sept.25,1877

Witnesses Inventor UNITED STATES PATENT OFFICE.

JAMES A. BOBB OF SAN FRANCISCO, CALIFORNIA.

IMPROVEMENT .IN SAW-MILL SET-WORKS- Specification forming part ofLetters Patent No. 195,650., dated September 25, 1877; application filedFebruary 16, 1877.

To all whom it may concern: v

Be it known that I, JAMES A. Roms, of the city and county of SanFrancisco, and State of California, have invented an Improvement inSaw-Mill Set-Works and I do hereby declare the following to be a full,clear, and exact description thereof, reference being had to theaccompanying drawings.

The principalobjectofmyinventionis tocombine a hinged supplemental stopattachment with the quadrant beside which the set-lever of a saw-millset-works operates, so that it can be. used to shorten the throw of thelever when it is desired to take out the width of the saw-kerf in sawingplanks of more than usual thickness.

The stop usually employed for limiting the movement of the set-lever ispermanently adjusted to a certain thickness of board, so that each throwof the" lever will move the standard a specified and uniform distance.If, however, it be desired to saw a board of double thickness, and thelever is given two throws or motions, each throw stopping at thepermanent stop, it is evident that the board will have an excess ofthickness equal to the width of the kerf which the saw would haveremoved if it had been run through the log after the first throw. Mysupplemental stop isintended to obviate this difiiculty by limiting eachmotion or throw of the lever, after the first motion of the lever hasbeen once made, in the ordinary way sufficiently to take out this excessof thickness.

My invention also includes a weighted brake for preventing the momentumof the hand-wheel from rotating the screw-shaft beyond the point towhich it is carried by the lever; also, an improvement in the screwrodswhich move the head-blocks, all as hereinafter described.

Referring to the accompanying drawings, Figure 1 is a perspective viewof my invention; Fig. 2, an enlarged view of the quadrant and stop, andFig. 3 a part of the screwshaft.

A A represent the set-shafts of a saw-mill, on one of which the ratchetB is secured, and C is the quadrant beside which the set-lever D, withits pawl, operates in the usual way to rotate the shafts.

E is the crank-wheel, by means of which the attendant rotates theset-shafts in order to return the head-blocks after each log is sawed.

F is the ordinary stop, which is secured to the quadrantC for thepurpose of stopping or providing a limit for the throw of the lever D,in order to regulate the thickness of, the board to be sawed.

My attachment consists of an adjustable plate, which I hinge orotherwise loosely attach to the stop F or quadrant C, as preferred, andwhich can be either dropped down upon the quadrant so as to form anextension of the stop F, as shown at Fig. l, or raised so as to stand upout of the way, as represented at Fig. 2. This attachment I make in twoparts, g h. The part 9 is loosely attached to the ordinary stop F, andhas a hook or side extension, 6, on its extremity, which will rest uponthe edge of the quadrant when the attachment is thrown down upon it. Thepart It is slotted, and a set-screw, 0, passes through the slot into theouter end of the plate 9, so that it can be extended or shortened, asdesired. The extremity of the plate h projects beyond the end of theplate g, and serves as a stop for the set-lever when the attachment isdown. The length of this attachment can be regulated to correspond withthe thickness of the saw by extending or shortening the plate It on theplate 9.

When boards of a uniform thickness are being sawed, the ordinary stop Fis adjusted to the proper point, but if it be desired to saw boards ofdouble the ordinary thickness, I first throw the lever the usualdistance against the ordinary stop, which moves the head-blocks theusual distance. If I should now move the head-blocks an equal distance asecond time without running the saw through the log, I would have aboard with an excess of thickness over the double thickness desiredequal to the width of the saw-kert'; but to avoid this, I drop theextension or supplemental stop, which shortens the second throw of thelever sufficiently to take out the thickness of the saw-blade, and thisis repeated as often as the thickness of the board is duplicated. Whennot in use, this supplemental stop is turned up out of the way.

It often happens that the screw'shafts are carried beyond the pointdesired by the m0- mentum imparted to it by the lever. To pre- -ventthis, apply a weighted brake, l, to the 1. The supplemental hinged stopg h, attached to the quadrant G, substantially as and for the purposedescribed.

2. A supplemental hinged stop, consisting of the hinged plate g with itsside extension or projection t and the slotted extension-plate h,arranged to be adjusted by means of the set-screw 0, in combination withthe quadrant O, set-lever D, ratchet B, and screwshafts A, substantiallyas and for the purpose described.

In witness whereof I have hereunto set my hand and seal.

JAMES A. ROBB.

Witnesses GEO. H. STRONG, OLWYN T. STACY.

